"Perfect Memorization" (完全記憶能力 Kanzen Kioku Nōryoku?) is the fourth episode of the first season of the Toaru Majutsu no Index anime series. It was first broadcast on October 25, 2008, and was directed by Kobayashi Kousuke and written by Akahoshi Masanao. Nishikiori Hiroshi returns to storyboard the episode along with Nakumura Noriyoshi.